Just rebuild it get a new diff. gear the best diff. balls you can afford, while your at it the idler gear which is nylon should be replaced check to make sure that the top shaft is in good shape also , if your using bushings change them out to bearings cost a little but well worth the money. The case bearing that the top shaft goes threw has a tendecy to wear and cause the top shaft to have play in it that travels to the idler gear and so forth. I could go on and on about these trannys but I'll stop here, RED